Shoulder and Proximal Upper Extremity Procedures

Shoulder surgery can be accomplished arthroscopically or open, and is usually performed in either a lateral decubitus (LDP) or beach-chair (BCP) position. The LDP involves placing the patient on their side on a padded table on top of a bean bag to support the pelvis and lower torso. For the BCP, the patient is placed on a table with a headrest and the bed is positioned in Trendelenburg, with the feet elevated to 15 degrees and the knees flexed to 30 degrees. Some potential advantages of the BCP over the LDP include shorter surgical times, less difficult conversion to an open procedure, and a lower incidence of neuropathies. The BCP can present a unique challenge for the anesthesia provider in accessing the airway and has been associated with rare, but catastrophic, neurologic complications, including transient visual loss, spinal cord ischemia, and strokes. These complications have been suggested to be from the gravitational effects of the sitting position and the blunting of cerebral autoregulation under general anesthesia (GA). There is some evidence that patients in the BCP have diminished cerebral autoregulation and lower regional cerebral oxygenation when compared to the LDP. This, however, does not relate to cognitive outcomes. It is still considered prudent to take into consideration the difference in where the blood pressure is measured (brachial or popliteal artery) in relation to the external auditory meatus. If not, significant cerebral hypotension may occur. From where the blood pressure is measured, there is a decrease of 0.77 mmHg in arterial blood pressure for every 1-cm elevation [Reference Johnson, Rishi and Andone1].

Traditionally, most shoulder surgeries are performed under GA, but can be performed using regional anesthesia as the primary anesthetic. Pain, especially dynamic pain, can be a significant factor after shoulder surgery impeding discharge and recovery, and is often managed using multimodal analgesia, including nerve blocks. Enhanced Recovery After Surgery (ERAS) protocols are becoming commonplace for total shoulder arthroplasties. Regional anesthesia utilized for shoulder surgeries includes cervical paravertebral, interscalene, supraclavicular, infraclavicular, superficial cervical plexus, suprascapular, axillary, and potentially erector spinae plane blocks. Interscalene blocks (ISBs) are the most effective and widely used, and are currently the gold standard. ISBs have 100% involvement of the ipsilateral phrenic nerve, so they may not be suitable for patients with underlying respiratory disease. The type and combination of regional anesthesia used for shoulder surgery should be based upon the type of surgery and patient comorbidities.

Interscalene brachial plexus block as a single-injection or continuous block is frequently used for perioperative analgesia in a variety of procedures, such as arthroplasty, Latarjet, proximal humerus osteosynthesis, acromioclavicular resection, shoulder luxation, clavicle osteosynthesis, rotator cuff repair, arthrolysis, acromioplasty, and Bankart’s repair, as well as various arthroscopic shoulder procedures. When combined with cervical plexus block, the ISB can be used to provide complete surgical anesthesia for the shoulder/proximal humerus and clavicle. Furthermore, to provide surgical analgesia for the entire shoulder for certain procedures with significant axilla involvement such as biceps tenodesis, the intercostobrachial nerve can be separately targeted, as discussed in “Distal Upper Extremity Procedures” (see Table 23.1). The phrenic nerve is almost always blocked during the ISB. The ISB is associated with hemidiaphragmatic paralysis (HDP). Alternative diaphragm-sparing nerve blocks include the suprascapular nerve block (SSB) and axillary nerve block [Reference Neuts, Stessel and Wouters2].

Distal Upper Extremity Procedures

Minor soft tissue operations of the hand, such as carpal tunnel release, can be done with local infiltration or intravenous (IV) regional anesthesia (or Bier block). However, for operations lasting >1hour, such as invasive procedures involving bones or joints, the brachial plexus block is the preferred regional anesthesia technique. The supraclavicular approach to the brachial plexus block (SCB) is commonly used for arm surgery at, or distal to, the elbow, including forearm and hand surgery. The SCB provides blockade to the musculocutaneous, radial, ulnar, and median nerves but fails to block the medial aspect of the upper arm supplied by the intercostobrachial nerve, which should be blocked separately. Special consideration also needs to be taken for the risk of phrenic nerve palsy, Horner syndrome, and recurrent laryngeal nerve palsy with the SCB. The infraclavicular and axillary approaches to the brachial plexus block share similar indications to the SCB, and target the cord and terminal peripheral nerves of the brachial plexus, respectively. The musculocutaneous nerve is often missed during the axillary block, as the nerve branches off the plexus prior to branching of the radial, ulnar, and median nerves. Under ultrasound guidance, the musculocutaneous nerve can be visualized laterally between the fascial planes of the biceps brachii and the coracobrachialis muscle, and can be traced distally with the probe turned longitudinally along the coracobrachialis muscle (see Table 23.1). Distal upper extremity surgeries can be performed under brachial plexus block with sedation as needed, or under GA with or without brachial plexus block.